GB2043741A

GB2043741A - Underground mining

Info

Publication number: GB2043741A
Application number: GB7850349A
Authority: GB
Original assignee: ROY RICH SERVICES Inc
Current assignee: ROY RICH SERVICES Inc
Priority date: 1978-12-29
Filing date: 1978-12-29
Publication date: 1980-10-08
Also published as: DE2952100A1; GB2043741B

Abstract

The invention is concerned with underground mine workings, primarily but not exclusively for the mining of coal by the "long wall" system. A coal cutting machine (6) is driven along the wall face (F) by the use of a haulage chain (14) anchored at opposite ends of the face. To avoid the problems associated with the establishment of slack chain behind the machine, take-up means (16, 18) is provided at at least the end of the working from which the machine undergoes a working traverse to remove material from the face. Control means is provided to render said take-up means operative, to take up the slack produced in the chain (14), during such a working traverse of the cutting machine (6), and to render the take-up means inoperative to provide a substantially fixed anchorage on a return traverse of the machine. Preferably such take-up means is provided at both ends of the working. <IMAGE>

Description

SPECIFICATION Improvements in or relating to underground mine working This invention is concerned with improvement in or relating to underground mine working. The invention has been particularly devised for the underground mining of coal, particularly by the system known as the "long wall" system. It will however be appreciated that the invention may be applied with advantage to the underground mining of other materials.

In an underground mine working of the "long face" type, a coal-cutting machine is conventionally driven along the face being worked by the use of a haulage chain which is anchored at opposite ends of the face. The haulage chain passes over a drive sprocket of the machine, whereby the machine hauls itself along the face from one end to the other, and back.

The haulage chain is conventionally 22 millimetre chain and a considerable force is applied to the chain during a hauling and cutting operation of the machine; typically this force is in the order of 20 tonf.

This force inevitably stretches the chain, and as the machine reaches one end of the face there is a considerable amount of slack behind the machine. Thus when the machine operates to cut in the reverse direction, the drive sprocket of the machine firstly pulls in the chain slack without resistance, and as the chain becomes taut, a shockforce is applied to the chain, which results in a shock loading not only to the drive sprocket, but also to the chain itself. Such shock loading is disadvantageous, in that it tends to accelerate breakage of the components. Additionally however, the chain tends to "whip" which may cause damage to other parts of the mining equipment, and could be dangerous to operatists in the vicinity.

Several suggestions have been made to reduce this problem; one such suggestion is to anchor the chain at opposite ends of the face to spring-or hydraulic-rams. Another such suggestion is to power the drive sprocket through a drive clutch.

However, no prior suggestion has been made which significantly reduces the problem, particularly on long faces, and/or on faces which are curved.

According to this invention there is provided an underground mine working in which traverse of the fact being worked by a coal-cutting machine is effected by the use of a haulage chain, in which fluid-powered take up devices are provided at opposite ends of the working and which are operative alternately to take up slack produced in the haulage chain by traverse of the face by the cutting machine.

However, whereas the invention above defined is particularly useful in workings in which a cut is taken in both directions of traverse, where there is a need for a take up device at both ends of the face being worked, in workings where a cut is taken in one direction of traverse only, and where the machine is returned to its start position without cutting, a single take up device may be provided at one end of the working only, or if a take up device is provided at the other end (viz, that end towards which the machine is returned free-running), this is operative under a lower power.

Preferably the or each such take up device comprises an hydraulic motor and a sprocket driven thereby, the haulage chain extending around said sprocket and operation of the hydraulic motor being effective to take in slack and to exert a pre-tension on the haulage chain. Such a pre-tension must clearly be lower than the force exerted on the haulage chain by the drive sprocket of the cutting machine, and is preferably between 7 and 15 tonf, conveniently being about 9 tonf.

In such a mine working, conveniently the or said take up devices are associated with control mechanism coupled with the cutting machine, said control mechanism being operative when the cutting machine travels in a first direction to lock out the first of the take up devices, rendering the sprocket thereof fixed, and to cause operation of the second, and when the cutting machine travels in a second, opposite direction, to lock out the second take up device, rendering the sprocket thereof solid, and to cause operation of the first take up device.

There will now be given a detailed description, to be read with reference to the accompanying drawings, of a mine working which is a preferred embodiment of this invention and which has been selected to illustrate the invention by way of example.

In the accompanying drawings:- FIGURE 1 is a plan view illustrating schematically the position of two take up devices in relation to a coal cutting machine; FIGURE 2 is a side elevation of Figure 1.

In the working which is the preferred embodiment of this invention, a coal cutting machine 6 comprising twin cutter drums 8, 10 is mounted for movement above a conveyor assembly 12, for traversing movement alongside a coal face F. A haulage chain 14 is anchored at opposite ends of the face (at the left and righthand ends of the drawing) by take up devices 16 and 18 respectively. The haulage chain passes through the housing of the coal cutting machine, around two idler sprockets 20, 20 and around a driven sprocket 22.

In a cutting operation of the machine 6, during traverse from right to left, the drive sprocket 22 is rotated in a clockwise direction (Figure 2) and the machine hauls itself along the chain 14 whilst the cutting drum 8 rotates to cut a band of coal from the seam, and to deposit the cut coal on the conveyor 12.

During such operation of the drive sprocket 22, slack haulage chain accomulates to the right of the machine 6.

Conversely, in a cutting operation of the machine during traverse from left to right, slack haulage chain accumulates on the left hand side of the machine.

Each of the take up devices 16 and 18 comprises a drive sprocket 17, 19 respectively, over which the haulage chain passes. The take up devices are hydraulically powered through a control device, which is associated with the operation of the cutting machine 6, in the following manner.

During operation of the machine 6, from right to left the drive sprocket 22 hauls the machine towards the left hand end of the face along the haulage chain 14, tending to accumulate slack haulage chain behind the machine, as a aforesaid. During this operation, the control device operates to "lock out" the device 16, rendering the sprocket 17 thereof solid, and providing a fixed point against which the force exerted on the chain 14 by the sprocket 22 (which is in the of 20 tonf) may act. Simultaneously the sprocket 19 of the device 18 is powered to take up the slack chain tending to accumulate behind the machine 6, retaining the haulage chain 14 taut under a force of approximately 9 tonf.

When the machine reaches the end of its run (that is reaches the left hand end of the face) and powered operation in the reverse direction is commenced under the direction of a mine operative, the control device 18 is locked out, rendering the sprocket 19 thereof solid. The haulage chain between the device 18 and the machine 6, along which the sprocket 22 is now travelling, is at this stage taut under the aforesaid tension of 9 tonf, and there is consequently little or no shock loading of the chain, and little or no "whip" thereof. Simultaneously, the device 16 is powered to rotate the sprocket 17, to apply a tension, similarly of approximately 9 tonf, to the length of chain now behind (to the left hand side) of the cutting machine 6, taking up slack as the machine 6 traverses the face towards the right hand end.

It will be appreciated that in underground mine workings in which a cut is taken by the machine in one direction of traverse only (for example in the direction from rightto left, Figure 1) and in which return of the machine to its start position is carried out in the absence of a coal cutting operation, during movement of the machine from left to right back to its start position, a considerably lower tension is exerted on the chain by the sprocket 22. In such circumstances, it may be possible to dispense with the take up device 16 at the left hand end of the face, or to operate this take up device at a lower work rate, in view of the smaller amount of slack which is produced in the chain 14 behind (that is, to the left hand side of) the machine 6.

Alternatively and/or in addition, and in particular where the sprocket 22 is driven through a clutch, since the power applied to the sprocket 22 on such return movement of the machine 6, the problems associated with the take up of slack by the sprocket 22 on commencement of such a return movement of the machine 6 will be smaller, and it may be possible to dispense with the take up device 18 at the right hand end of the face, or operate said take up device under a lower power.

Most conveniently the take up devices 16 and 18 are provided by "Staffa" hydraulic motors, and the sprockets 17 and 19 are in the form of five-toothed sprockets. As the devices 16 and 18 operate in turn, conveniently slack chain accumulated thereby is merely deposited in an adjacent container.

Claims

CLAIMS 1. An underground mine working in which traverse of the face being worked by a coal cutting machine is effected by the use of a haulage chain, in which fluid-powered take up devices are provided at opposite ends of the working and which are operatively alternately to take up slack produced in the haulage chain by traverse of the face by the cutting machine. 2. An underground mine working according to Claim 1 in which the take up devices each comprise an hydraulic motor and a sprocket driven thereby, the haulage chain extending around said sprocket and operation of the hydraulic motor being effective to take in slack and to exert a pre-tension on the haulage chain. 3. An underground mine working according to Claim 2 in which the tension exerted by the hydraulic motors, when operative, is between 9 and 15 tonf. 4. An underground mine working according to Claim 3 wherein the tension is about 9 tonf. 5. An underground mine working according to any one of the preceding claims wherein, when one of the take up devices is operating, the other is "locked out". 6. An underground mine working according to any one of the preceding claims wherein the take up devices are associated with control mechanism coupled with the cutting machine, said control mechanism being operative when the cutting machine travels in a first direction to lock out the first of the take up devices, and to cause operation of the second, and when the cutting machine travels in a second, opposite direction, to lock out the second take up device and to cause operation of the first take up device. 8. An underground mine working in which traverse of the face being worked by a coal cutting machine is effected by the use of a haulage chain, and in which a cut is taken in one direction of traverse only, in which a fluid-powered take up device is provided at one end of the working, having a sprocket around which the haulage chain extends, and which is operative as the machine traverses the face in at least one direction, to take up slack produced in the haulage chain by such traverse New claims filed on 24/12/79 Superseded claims 1-6 and 8 (no claim 7). New or amended claims:- 1-11. CLAIMS

1. An underground mine working in which traverse of the face being worked by a coal-cutting machine is effected by the use of a haulage chain, in which fluid-powered take-up devices are provided at opposite ends of the working and which are operative alternately to take up slack produced in the haulage chain by traverse of the face by the cutting machine.

2. In or for an underground mine working in which the material to be mined is removed from a face of the working by a cutting machine traversed along the face, the combination of a haulage chain adapted to co-operate with a drive element on the cutting machine, and a fluid-powered take up means at that end at least of the working from which the machine undergoes a working traverse to remove the material from the face, wherein said take up means serves to take up slack in the haulage chain during such traverse of the face and control means is provided for rendering the take up means operative to take up the slack, or inoperative to provide a substantially fixed anchorage in co-ordination with the direction of traverse of the machine.

3. The combination according to Claim 2, wherein the machine is of a form to be operative to remove material from the face in each of its opposite directions of traverse therealong and one of said take up devices is provided at each end of the haulage chain.

4. The combination according to Claims 2 and 3, wherein the or each take up device comprises a rotary hydraulic motor and a sprocket driven thereby, the haulage chain extending around said sprocket.

5. The combination according to Claim 4, wherein the tension in the haulage chain exerted by the or each hydraulic motors, when operative, is between 9 and 15 tonf.

6. The combination according to Claim 5, wherein the tension is about 9 tonf.

7. The combination according to any one of the preceding claims, wherein, when one of the take up means is operative, the other is locked out.

8. The combination according to any one of Claims 2 to 7, wherein the control means is responsive to a parameter related to the direction of traverse of the cutting machine to lock out of operation the, or each of the, fluid-powered take up means at that end of the face towards which the machine is undergoing a working traverse.

9. An underground mine working at which is installed the combination of apparatus claimed in any one of Claims 2 to 8.

10. An underground mine working comprising apparatus substantially as hereinbefore described with reference to the accompanying drawings.

11. In or for an underground mine working, the combination of apparatus constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.